We continue to clarify the role ofthe catecholamines and indole amines brain systems in various obese syndromes including genetcally obese mice and rats, made obese by brain lesions. We plan to extend this work to a species that has a dietary type of obesity such as the sand rat or acomys carrhimous. We expect to be ablethis year to extend our analysis to include tyrosine hydroxylase activity. Also we now have the capacity to begin microfluormetric work on single neurons in nucleus solatarius and other brain areas. Several interesting precautions have been uncovered by the work including the necessity for assessng non-specific damage when using 6-0 H dopamine or 5, 6 dehydroxytryptamine to lesion the brain. Also we have found that simple isolation of a rat is sufficient to cause large increases in the fluorescent intensity of catecholamine cells in nucleus solatarius.